The WikiLeaks release this week of thousands of classified documents on the war in Afghanistan has reignited the political debate over the direction of the war and overall U.S. national security, an issue that former House Speaker Newt Gingrich is due to tackle Thursday in a speech at the American Enterprise Institute. Gingrich weighs in at a moment when the Republican Party is more divided on national security than it has been in decades.

The recent intraparty battering of Republican National Committee Chairman Michael Steele — after his comments that characterized Afghanistan as virtually hopeless and called it “a war of Obama’s choosing” — was really only a sideshow to this bigger story. The last time Republicans were so sharply at odds was the party’s debate with its isolationist wing before World War II.

Dissension in the Republican ranks was on full display in the conservative reactions to the Obama administration’s National Security Strategy this spring. Conservative foreign policy analysts couldn’t decide whether to accuse the Obama administration of plagiarism or treason. Some praised the strategy as a continuation of the Bush administration’s approach; others condemned it as a recipe for weakness and an appeasement of America’s enemies.

This Republican national security confusion and cacophony is strongest on three issues.

First is arms control and nuclear policy. Former Massachusetts Gov. Mitt Romney and Arizona Sen. Jon Kyl have criticized the new START with Russia, while prominent Republican national security leaders like James Baker, Henry Kissinger, James Schlesinger and Brent Scowcroft have all supported it.

Indiana Sen. Dick Lugar, the ranking member on the Senate Foreign Relations Committee, entered the fray earlier this month, saying Romney’s critique of the new START treaty was a “hyperbolic attack” based on “misreading and myths.”

This division among Republicans widened into a chasm during President George W. Bush’s first term. That administration questioned decades of bipartisan arms control and nuclear policy, influenced by figures like John Bolton, a former State Department official who was deeply skeptical of international treaties and the United Nations. And it is likely to be on full display as conservatives gear up for a legislative battle to defeat a new arms-control measure grounded in the ideas of President Ronald Reagan.

The second issue dividing Republicans is spending and defense. Here, trouble has been brewing for several years, growing out of the Bush administration’s tax cuts and spending increases in many areas — including defense. This helped to take the country from record budget surpluses under the Clinton administration to record deficits over the past decade.

For years, Republicans papered over the differences between the tax-cutting “small government” proponents and the security hawks who rejected even the most sensible cuts in wasteful defense spending.

One recent example is former Gov. Sarah Palin’s criticism of Defense Secretary Robert Gates, a holdover from the Bush administration, for saying that certain defense cuts were needed.

With the rise of the tea party movement and the emergence of presidential candidates like Rep. Ron Paul, it is no longer possible for Republicans to ignore this division — especially if the party wants to play a meaningful role in the deficit debate.

Third, there is considerable Republican division about the war against Al Qaeda and other terrorist networks. Some conservatives make the political case that the Obama administration is making the country less safe from terrorists. Former Vice President Dick Cheney, for example, has repeatedly slammed the Obama administration for projecting weakness and giving “aid and comfort” to terrorists.

Contrast this with the views of some other former Bush administration officials. When asked if Obama’s and Bush’s counterterrorism policies are similar, John Bellinger, a former Bush official on the National Security Council and State Department legal adviser, said, “Absolutely.”

Former Secretary of State Colin Powell, who served in the Reagan and both Bush administrations, agreed. “I don’t know where the claim comes that we are less safe,” Powell said earlier this year.

In addition, Republicans frequently seem to criticize policies they supported when the Bush administration was in charge. The failed Detroit bombing plot on Christmas Day prompted several Republican leaders to criticize the handling of the suspected bomber and say the administration erred in reading him his Miranda rights and delivering him up for a civilian trial. Yet the Bush administration used this approach regularly, including in the 2001 “shoe bomber” case of Richard Reid.

So when Gingrich takes the podium Thursday in what is expected to be an attack on the Obama administration’s national security policy, he will be addressing a Republican Party that faces considerable challenges in reconciling its own competing visions on foreign policy.

Even as the midterm elections approach and the 2012 presidential race is discussed, Republicans have shown little sign that they will come together on security.

The renewed Afghanistan debate will further highlight these divisions. The Bush administration’s “global war on terror” and overall reckless approach to foreign policy may end up doing to Republicans what the Vietnam War did to Democrats for many years: leave them stuck in the past as they refight defense policies, internally divided and searching for a coherent message on national security.

Brian Katulis is a senior fellow for national security at the Center for American Progress Action Fund.